CVE-2024-26686 fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats

Medium 5.5 Published Updated

A local attacker can cause a hard lockup in the Linux kernel by triggering a race condition in the proc filesystem, leading to system denial of service.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Local or same network only
Victim action needed
Not needed
Fix
Available

What is CVE-2024-26686?

CVE-2024-26686 is a medium-severity denial of service vulnerability in Linux kernel, published on 3 Apr 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats

lock_task_sighand() can trigger a hard lockup. If NR_CPUS threads call do_task_stat() at the same time and the process has NR_THREADS, it will spin with irqs disabled O(NR_CPUS * NR_THREADS) time.

Change do_task_stat() to use sig->stats_lock to gather the statistics outside of ->siglock protected section, in the likely case this code will run lockless.

Weakness: CWE-667

Which versions are affected by CVE-2024-26686?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-26686?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2024-26686 being exploited?

There is no known exploitation of CVE-2024-26686 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as AZL-58704, AZL-58789, BELL-CVE-2024-26686, DEBIAN-CVE-2024-26686, GHSA-mgx5-jrhq-g7rg, ROOT-OS-UBUNTU-2204-CVE-2024-26686 and 1 more.

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